Electrical apparatus



July 24, 1956 J. KNUDSON ELECTRICAL APPARATUS 2 Sheets-Sheet 1 FJ' led Sept. 13 1951 F'IG.2.

TO STAETEE 0 BY I I; oOaZe, 62.64am, ATTORNEY y 24, 1956 G. J. KNUDSON ELECTRICAL APPARATUS 2 Sheets-Sheet 2 Filed Sept. 15 1951 F'IG.7.

INVENTOR. fill inmlfi /nadam BY FIG. 5.

4 T TOQNEX United States Patent ELECTRICAL APPARATUS Giltner J. Knudson, Guilford, N. Y., assignor to Bendix Aviation Corporation, New York, N. Y., a corporation of Delaware This invention relates to electrical apparatus and more particularly to apparatus for distributing electrical energy from a source to a plurality of circuits, such as in the ignition system of an internal combustion engine.

One of the objects of the present invention is to provide an improved distributor for high voltage currents which is adapted for use in the ignition systems of multi-cylinder internal combustion engines.

Another object of the invention is to provide a novelly constructed ignition distributor which may be made smaller than previously known structures of similar capacity without decreasing the safety factor against electrical flash-overs.

Still another object is to provide an ignition distributor embodying a novel terminal connection for the electrical cables detachably connected with the distributor electrodes to effect an electrical seal that will prevent flash-overs at high altitudes.

A further object is to provide a novel dual ignition distributor which is so constructed as to permit the use of a vibrator or similar type starting booster without danger of undesirable flash-overs between the current carrying electrodes.

The above and further objects and novel features of the invention will more fully appear fro-m the following detail description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a side elevation, mostly in section and with parts broken away, of one form of ignition distributor embodying the invention;

Fig. 2 is a diagram of an ignition circuit embodying the distributor of Fig. 1;

Fig. 3 is a top plan view showing the rotor of the distributor illustrated in Fig. 1;

Fig. 4. is a sectional view of said rotor, the plane of the section being indicated by line 44 in Fig. 3;

Fig. 5 is a bottom view of said rotor;

Fig. 6 is a sectional view of the electrode block of said distributor, the section being taken substantially on the line 66 of Fig. 7; and

Fig. 7 is a bottom view of said electrode block.

The single form of the invention illustrated in the drawings, by way of example, is embodied in an ignition distributor for directing electrical impulses simultaneously to pairs of spark plugs in each of four cylinders of an engine, the four pairs of spark plugs being served in predetermined sequence and in timed relation. Said distributor is also adapted to distribute a shower of electrical impulses from a single source to a set of four of said spark plugs including one of each of said pairs. The latter is desirable in starting the engine where the main sources of electrical energy are magnetos which do not 2,756,268 Patented July 24, 1956 iCC produce sufiicient energy at the speed imparted thereto by the starting motor.

In the form shown, said distributor comprises a rotor 19 and a stationary electrode block 11 which are hereinafter described in detail. Said rotor is suitably mounted on and rotatable with an engine drive shaft 12 between diametrically disposed input electrodes 13 and 14. The iatter are connected to the secondary windings 15 and 16, respectively, of ignition coils L and R of a dual magneto, which coils are diagrammatically represented in Fig. 2. Said electrodes are mounted in insulating blocks supported in the casing 17 of the magneto which may be of any suitable known construction and is accordingly not illustrated in detail. Electrode block 11 is secured within a housing member 18, such as by means of a plurality of stud bolts 19, and member 18 is in turn secured to magneto casing 17 with the rotor 10 and electrode block 11 in cooperative relation.

The novel rotor 10 in the form shown comprises a hollow or recessed body 20 of insulating material having embedded therein two diametrically disposed electrode bars 21 and 22 (Figs. 3 and 4) which in turn have pick-up electrode tips 23, 24 and 25, 26, respectively, at the ends thereof and spaced at intervals from each other. Said electrode tips are in the plane of supply electrodes 13 and 14 and project from the periphery of rotor body 20 sufliciently to successively pass said supply electrodes in spark gap relation therewith, as is best seen in Fig. 2. Upon counterclockwise rotation of the rotor, as viewed in Fig. 2, it will be seen that electrode tips 23, 24, 25 and 26 successively pass electrode 13 in that order, while electrode tips 25, 26, 23 and 24 pass in spark gap relation to electrode 14 during each complete rotation of the rotor. Thus, each electrode bar 21 and 22 is efiectively connected twice in succession with coil winding 15 and then twice in succession with coil winding 16, an electrode tip of one bar being adjacent one supply electrode each time an electrode tip of the other bar is ad jacent the other supply electrode to thus provide dual ignition in each engine cylinder in a known manner.

Bar 21 carries a third electrode tip 27 which projects from the outer periphery of rotor body 20 in a plane above tips 23 and 24 and separated therefrom by a rib 29 on the body. Similarly, bar 22 has a third electrode tip 28 which, however, projects inwardly into the recess in said rotor body and is preferably in still a different horizontal plane. During each revolution of rotor 10, tip 27 passes in spark gap relation to an outer ring of output electrodes a, b, e and f to be next described, and tip 28 passes in spark gap relation to an inner ring of output electrodes 0, d, g, and it. Thus, each coil winding 15 and 16 supplies energy first to two inner ring electrodes and then to two outer ring electrodes during each revolution of the rotor.

The electrode block 11 consists of a body 30 of insulating material having an outer skirt 31 and an inner skirt 32 between which there is an annular recess into which rotor 16 extends. The stationary electrodes (1 to h are preferably molded into hollow bosses in block body 30. Each said electrode extends downwardly from its boss, as viewed in Fig. 1, and the upper end thereof is exposed at the inner end or bottom of the recess in said boss. A comically coiled spring 33 is preferably removably secured to the upper or outer end of each output electrode. The output electrodes of each ring are evenly spaced, i. e., at 90 intervals in this instance, and those of the inner ring are offset 45 (or one-half of the angle between adjacent electrodes) from those of the outer ring. Thus, the electrode tips 27 and 28 are at a safe distance from the inner and outer ring electrodes, respectively, when an electrical impulse is passing through the distributor.

The outgoing insulated cables or leads 34 which connect the output electrodes with the spark plugs are provided with terminals which are novelly associated with electrode block ll to insure at high altitudes the maintenance of pressure which may be artificially supplied within the magneto and distributor casing 17, 18, and to effect an electrical seal for preventing flashovers from the electrodes to ground, particularly at high altitudes. As shown, said terminals comprise a resilient insulating sleeve 35 closely surrounding cable 34. The insulation is stripped from the end of the cable and the wire or conductor thereof passes through an internal flange 36 of resilient sleeve for soldered connection or other suitable attachment with a metal washer 3'7 engaged by spring 33. An external flange 38 on sleeve 35 engages a shoulder 39 in recess 49 and said engagement is yieldably maintained by a coil spring 41 interposed under compression between said flange 38 and a split ring 42 removably mounted in a groove in the wall of said recess. The spring 4-1 is also effective to squeeze sleeve 35 radially inwardly to tightly engage cable 34.

The above-described distributor is illustrated diagrammatically in an ignition circuit in Fig. 2. The normally operating ignition circuit embodies two ignition coils which may be, but need not necessarily be, embodied in a single dual type magneto. The left coil L comprises secondary winding 15 and a primary winding 45 while the right-hand coil R comprises secondary winding 16 and a primary winding 46. The primary windings may be simultaneously energized by a magnetic rotor or other magnetic means well known in the art and the circuits therethrough may be periodically broken by cam operated circuit breakers 47 and 43, respectively, to cause high voltage impulses to be simultaneously induced in secondary windings l and 16 at times when supply electrodes l3 and 14 are in spark gap relation with electrode I tips 23, 24, 25 or 26, as above described. A switch 49 is provided for grounding coils L and R when it is desired to render the system inoperative.

When starting the engine, particularly at high altitudes or under low temperature conditions, it is desirable to supply a shower of sparks to each engine cylinder during a wider arc of crankshaft rotation than is necessary or desirable during normal engine operation. The novel construction of the distributor makes this feasible without making the same undesirably large in diameter. While the engine crankshaft is turned slowly by a starting motor (not shown), the latter and the ignition circuit are supplied with electrical energy from a battery 50 through a starter switch 51. Current from the battery passes through a solenoid coil 52 which electro-magnetically closes a switch 53 that is normally held in open position by a spring 54.

When switches 51 and 53 are both closed, current flows from the battery through vibrator coil 55, the normally closed switch 56, switch 53 and lead 57 to terminal 58. Coil 55 and switch 56 cooperate to function as a vibrator in a well-known manner and thereby cause an interrupted direct current to flow through lead 57. From terminal 58 the major portion of the current flows through circuit breaker 47 to ground when the breaker contacts are engaged, but through primary coil 45 to ground while said contacts are disengaged, as illustrated in the drawings. As circuit breaker 47 is periodically opened and closed, the interrupted flow of current through winding 45 induces high voltage impulses in secondary winding 15, which impulses are delivered through supply electrode 13, an electrode tip, such as tip 23, bar 21, electrode tip 27, output electrode a and cable 34 to a spark plug (not shown) in one of the engine cylinders. A shower of sparks will thus be produced at a spark plug during the time that breaker 47 is open and tips 23 and 2.7 are in spark gap relation with electrodes 13 and a, respectively. Although this sparking may continue after electrode tip 27 has passed electrode a a substantial distance, there is no danger in the novel construction illustrated of any flash-overs between said tip 27 and the next nearest output electrode c which is on the inner ring. It will be seen that showers of spark impulses will thus be directed in timed relation via electrodes 12, c, and d to a spark plug in each of the other three cylinders of the engine as electrode tips 24, 25 and 26, respectively, pass supply electrode 13. When the engine has started, switch 51 is released to open position and the engine will then receive dual ignition from coils L and R.

There is thus provided a novel and advantageous ignition distributor which is especially adapted for use on multi-cylinder engines in conjunction with the best available booster systems for starting the engine. The novel construction of the distributor makes it possible to attain the desired results with a structure which occupies a minimum of space while preserving the safety factor against flash-overs. Novel terminal sealing means are also provided to insure substantial gas and moisture tightness as well as electrical tightness for the prevention of ignition failures, especially at high altitudes.

Although only one embodiment of the invention is herein illustrated and described in detail, it is to be expressly understood that the same is not limited thereto. For example, the invention may be embodied in ignition distributors designed for engines of more or less than four cylinders and for engines with single, as distinguished from dual ignition. Various other changes may also be made, particularly in the specific design and arrangement of the parts illustrated, without departing from the spirit and scope of the invention, as will now be apparent to those skilled in the art.

What is claimed is:

1. In an ignition distributor, two diametrically disposed supply electrodes, a rotor mounted for rotation between said supply electrodes and having a recess in the end of the body thereof, a plurality of spaced electrode tips projecting radially from said rotor for movement past said supply electrodes in spark gap relation thereto, said tips being electrically connected in diametrically disposed groups by conductors embedded in the rotor body, an outer electrode tip connected to one of said conductors and extending radially outward from the rotor in axially spaced relation to the plane containing said first-named electrode tips, an inner electrode tip connected to the other of said conductors and extending radially inward into said recess, an outer ring of circumferentially spaced output electrodes in spark gap relation to the path of said outer electrode tip, and an inner ring of circumferentially spaced output electrodes projecting into said recess in spark gap relation with the path of said inner electrode tip, each electrode of said inner ring being on a radius extending between the adjacent electrodes of said outer ring, said output electrodes being mounted in an insulating block.

2. An ignition distributor as defined in claim 1, wherein the radii extending through the electrodes of said inner ring extend midway between adjacent electrodes of said outer ring.

3. An ignition system comprising a distributor as defined in claim 1, and magneto-motive means for simultaneously supplying electrical impulses to said supply electrodes when said spaced electrode tips are in spark gap relation therewith.

4. An ignition system as defined in claim 3 comprising vibrator means for supplying electrical energy to at least one of said supply electrodes at the will of an operator.

5. Apparatus as defined in claim 1 comprising an insulated cable connected to the outer end of each of said output electrodes and means including a resilient sleeve and a coil spring under compression engaging said sleeve for compressively filling an annular space around each of said cables in a recess in said insulating block.

6. In an electrical current distributor, two sets of circumferentially spaced output electrodes mounted on concentric circles, a rotor having an annular portion projecting between said sets of electrodes, an inner electrode tip on said rotor in spark gap relation with the inner set of output electrodes, an outer electrode tip on the rotor in spark gap relation with the outer set of output electrodes, and a single means for supplying pulses of electrical energy alternately to said inner and outer electrode tips from a source of electrical energy.

7. Apparatus as defined in claim 6 wherein said energy supplying means includes a stationary input electrode and diametrically disposed sets of electrode tips on the rotor, each said set comprising a plurality of circumferentially spaced electrode tips mounted on the rotor to successively pass in spark gap relation with said input electrodes, one said set of electrode tips being electrically connected to said outer electrode tip and the other said set being electrically connected to said inner electrode tip.

8. Apparatus as defined in claim 7 comprising a second input electrode for connection to a second source of electrical energy, said second input electrode being diametrically disposed with respect to the first-named input electrode and so positioned that the electrode tips of said sets pass in spark gap relation thereto during rotation of the rotor.

9. Apparatus as defined in claim 6 comprising an insulated block in which said output electrodes are mounted, the outer end of each said output electrode terminating in a recess in said block, said recess having an outwardly facing shoulder, an insulated cable connected to said output electrode in said recess, a resilient sleeve closely surrounding a portion of the cable in said recess and having a flange engaging said shoulder, a retaining ring removably mounted in an annular groove in the wall of said recess, and a coil spring under compression interposed between said flange and said retaining ring, whereby said sleeve is caused to yieldably, compressively engage said shoulder and cable.

10. In an ignition distributor or the like, an insulating block, an electrode embedded in said block, one end of said electrode terminating in a recess in said block, an insulated cable extending into said recess and electrically connected to said electrode, and means for sealing the space around a portion of said cable in said recess including a resilient sleeve closely surrounding the cable, said sleeve having a flange seated on a shoulder in said recess, and a spring removably held in said recess under compression against said flange, whereby said sleeve is held in compressive engagement with said shoulder and the cable.

11. Apparatus as defined in claim 10 including means for securing said sleeve to the end of said cable and resilient means for electrically connecting the cable to said electrode.

12. Apparatus as defined in claim 10 including a split ring seated in an annular groove in the wall of said recess for retaining said spring in said recess.

References Cited in the file of this patent UNITED STATES PATENTS 2,024,015 Spengler Dec. 10, 1935 2,035,947 Davis, Jr Mar. 31, 1936 2,060,606 Bowlus Nov. 10, 1936 2,243,269 Von Tavel May 27, 1941 2,286,232 Scott June 16, 1942 2,391,854 Hartzell Dec. 25, 1945 2,441,922 Schwarzmann et al May 18, 1948 2,571,774 Spengler et a1 Oct. 16, 1951 

